1. Field of the Invention
A polyurethane whose surface is treated with a block copolymer Of a 2-(2-perfluoroalkylethyl)-2-oxazoline and 2-methyl- or 2-ethyl-2-oxazoline has improved biocompatability and is suitable for use as a vascular graft.
Polyurethanes have relatively good biocompatability with blood and other body fluids, and have been used for artificial implants where there is blood contact, such as vascular grafts and artificial heart parts. However, as with all implants, any lack of biocompatibility is always a concern, and improvements are, of course, always desirable. The instant invention improves the biocompatability of polyurethane surfaces by treatment of the surfaces with selected polyoxazolines.
2. Technical Background
U.S. Pat. No. 3,483,141 reports the preparation of polymers of the containing the repeat unit ##STR1## wherein m is 2 or 3 and R may be CF.sub.3 (CX.sub.2).sub.n --, where n is an integer from 0 to 15 and X is hydrogen or halogen, especially chlorine or fluorine. The fluorine containing polymers are reported to be useful as water-and oil-repellent coatings for leather and fabric. There is no mention in this patent of treating polyurethanes or of biocompatability.
U.S. Pat. No. 3,300,274 discloses that polymers with the repeat units ##STR2## wherein y is 1 to 18 and x is 0 to 18. These polymers (and the aziridines from which they are made) are reported to be useful for treatment of (artificial and natural) fibers and textiles to enhance their oil and water repellency. There is no mention in this patent of treating polyurethanes or of biocompatability.